1. Field of the Invention
The present invention relates to a fiber body for use in a container for containing liquid to be supplied to liquid ejecting heads for ejecting liquid for recording, and to a liquid container containing the above fiber body.
The present invention also relates to a material surface reforming method to modify wetting characteristics of the surface of fiber itself or fiber having been subjected to some treatment thereon, which is used as a negative pressure producing (generating) member in a liquid containing container, through modifying its properties and characteristics, and to a negative pressure producing member having been subjected to the above surface reforming.
In particular, the present invention relates to a surface reforming method by which surface reforming of fiber consisting of an olefin resin, which is environment friendly but hard to subject to surface treatment, can be achieved without failure, to fiber having a reformed surface, and to a method of producing the same.
2. Related Background Art
In the ink jet recording field, an ink tank (ink container) through which a negative pressure is applied to recording heads have been used so as to prevent the leakage of ink. This type of ink tank contains a porous body or fiber body and, due to the capillary attraction of the porous body or fiber body, it holds ink and produces a negative pressure. Of the type, the ink tank containing a fiber body is particularly preferable in that, if the fiber body is arranged in such a manner as to keep its direction almost horizontal, the interface between ink and gas is kept horizontal even with fluctuations caused by the environmental changes, and hence, subjected to less variations in the direction of gravity.
As a fiber body contained in an ink tank, those obtained by spinning olefin resins are used in view of its easiness to recycle, because the casing of the ink tank consists of olefin resins such as PE (polyethylene) and PP (polypropylene). Since the wettability of olefin resins by ink, in particular, ink having a high surface tension such as black ink is poor, when injecting ink into an ink tank containing a fiber body consisting of an olefin resin, the vacuum injecting method is employed to forcibly inject ink into a tank in which a vacuum has been drawn.
On the other hand, in the field of ink jet recording today, in order to obtain images of higher quality and ensure high fastness properties of the ink deposited on a recording medium, the improvement of ink itself is making steady progress. To be concrete, pigment ink has come into use so as to improve to water (water-resistance) and a solvent is added to ink so as to heighten the fixing properties to a recording medium.
In the ink tanks currently in use which contain a fiber body consisting of an olefin resin, however, since ink is injected into an ink tank by the vacuum injecting method, as described above, it is necessary to draw a vacuum in the tank, accordingly, the processes and equipment are becoming more complicated. On the other hand, with respect to improvement of ink itself, the use of pigment ink and addition of a solvent to ink causes the viscosity of ink to be increased. As a result, the ability to supply ink to a recording head diminishes, and the higher recording speed becomes, the more supplying ink becomes unlikely to catch up with the recording speed.
The properties and characteristics of an element itself are dependent on the properties of its constituents, and the element has been given desired properties by modifying the properties of the constituents on its surface. The elements given desired properties include, for example, those having on their surface reactive groups having reactivity such as water repellency and hydrophilic nature or reactive groups reactive with an adduct.
In the surface reforming technology currently in use, generally, the surface of an element is made to have a radical with ozone or UV or ozone in combination with UV and the element having a desired property is formed simply by chemically linking the radical with the primary ingredient of a surface treatment agent.
There is another technology in which the surface of an element is not made to have a radical, but a surface treatment agent having a desired property itself is attached to the element, so as to obtain the desired property momentarily; however, the desired property thus obtained does not last.
In particular, in the surface reforming of giving an environment-friendly olefin resin hydrophilic nature, only the technology has been known to obtain a temporary and partial hydrophilic state by intermingle a surfactant with the olefin resin in the presence of water.
In order to form an additional layer on an element, an adhesive and a primer have been used. When using a primer, such as a silane coupling agent, which only reacts and links with the surface of the element, the element itself needs to be treated so that it can react with the agent.
The technologies using a primer include, for example, the one using a primer consisting of the same material system as that of the element so as to utilize its affinity for the element. As a primer of this type, acid-modified chlorinated polypropylene has been known which is used when providing a facing material of polyurethane resin on the element of polypropylene. When using the same material system as that of the surface of the element, however, the volume of the element is inevitably increased, in addition, the technology is needed for applying a uniform and thin coating on the element. Moreover, when the element is fine or porous, it is impossible to apply a uniform coating on such an element to its interior. In particular, acid-modified chlorinated polypropylene is not soluble in water, accordingly, it cannot be used in the form of a water solution, and its applications are limited.
Accordingly, it can be said that there has been no surface treatment agents, including those using the different material system from the surface of the element, which can exist in the form of a water solution and be used in uniform and thin surface reforming irrespective of shape of the element.
On the other hand, with respect to PE and PP, each constituting a fiber body, their wettability by ink is poor (the contact angle to water is 80xc2x0 or more), though it varies depending on the type of ink. Accordingly, in cases where PE or PP is used in a fiber body of an ink tank, a process of drawing a vacuum in the tank has been inevitably employed in injection of ink into the fiber body. This has required preparation of an injecting apparatus, causing the manufacturing process of the ink tank to be more complicated.
In addition, in the use of ink jet printers in recent years, with steady progress toward higher image quality and a wider variety of ink, there have been growing tendencies to add a solvent to ink, so as to increase the ink""s ability to fix on paper, and to use pigment in ink. This, however, causes the viscosity of ink to be increased, and hence, the resistance to ink flow in a fiber body to be increased. As a result, there arises a problem that supplying ink is unlikely to catch up with the printing speed, while the printing speed tends to increase more and more in the latest printers.
There have been used ink tanks having a pressure contact body, which consists of a bundle of fiber arranged in the direction of liquid supplying, placed in its liquid supply opening for supplying liquid to a recording head. In these tanks, too, there arises a problem that, when the resistance to ink flow in the pressure contact body is increased, even if ink supplying in a high flow rate is demanded, supplying ink is unlikely to catch up with the demand, from the viewpoint same as above.
The present invention is an epoch-making invention, which has been made based on the new knowledge and findings obtained during the investigation of the current technology standard.
With the surface reforming technology currently in use, in which the surface reforming is carried out simply by chemically linking the primary ingredient of a surface treatment agent with a radical produced on the surface of an element to be subjected to reforming, a uniform surface reforming cannot be achieved for the surface having a complicated topology, to say nothing of the interior portions of the negative pressure producing members having a complicated porous portion therein, such as sponge and composite fiber body used in the ink jet field.
Further, the use of the technology in which a surfactant is intermingled with the surface of an element in the presence of liquid can never achieve surface reforming for a porous body itself. When the surfactant is exhausted, the properties obtained are lost, and the properties of the surface immediately return to those of the surface itself.
Thus, it goes without saying that, for an olefin resin, which has such an excellent water repellency that its contact angle to water is 80xc2x0 or more, there has been no surface reforming method by which it is allowed to have a desired lyophilic nature for a long time of period.
Accordingly, the present inventors continued to investigate a method of conducting surface reforming on the surface of an olefin resin rationally and maintaining the reformed properties for a long time of period, while aiming at providing a method applicable to the surface reforming of any elements by clarifying the above method. After such an investigation, the present inventors directed their attention to using a liquid-type surface treatment agent on the assumption that the use of the liquid-type surface treatment agent would enable the surface reforming even for such negative pressure producing members as have a complicated shape.
At the same time, the present inventors newly found that the use of the surface energy in the relationship between the surface of a negative pressure producing member, which is to be reformed, and polymer having a reactive group makes it possible to control the balance of the surface and the reactive group and keep it in a desired state and that the analysis of the polymer itself enables the achievement of further improvement in durability and further stability in quality of the ink.
Further, the present inventors directed their attention to negative pressure properties of a negative pressure producing (generating) member such as porous body, from the different viewpoint, and newly recognized a problem as described below.
In most cases negative pressure producing members currently in use are exposed to liquid at all times, and in some cases, even where a negative pressure chamber and a liquid containing chamber constitute an integrally formed unit, once liquid has been exhausted in part of the member which is to be exposed to liquid, the part is replenished with liquid; however, generally it is not assumed that the negative pressure producing members in state where liquid has been exhausted is replenished with liquid as is done in the ordinary apparatus. Thus, it has not yet been recognized even by those skilled in the art whether the negative pressure of a negative pressure producing member and the amount of liquid held by the same will return to their initial states even after replenishing the member with liquid.
The present inventors examined how far the negative pressure of a negative pressure producing member and the amount of liquid the same holds will return to their initial states when a replenisher containing chamber (container or tank) is mounted after the liquid contained in a chamber for containing a negative pressure producing member is exhausted at an arbitrary level. As a result, there was observed a tendency such that, for the liquid filled into the negative pressure producing member initially, the amount of the liquid held by the member was considerably close to that of the initial state because the liquid was forcibly injected in some way, however, after simply repeating the replenishment, the amount became about a half as much as that of the initial state. This is probably because the air in the negative pressure producing member is hard to remove. And as the liquid was repeatedly replenished, the amount of the liquid held by the negative pressure producing member became smaller and the negative pressure was increased.
The present inventors concentrated their energies on examining the problems as described above and have finally found that subjecting the surface of the fibers consisting of PE and PP to the surface treatment of giving hydrophilic nature thereto improves the wettability by ink and decreases the resistance to flow during the ink""s movement, and moreover, what type of the surface treatment gives them a long-term hydrophilic nature. Furthermore, the present inventors have come to understand that the surface treatment of giving hydrophilic nature can be developed more rationally using such a treatment in a desired area of the fiber body, as a negative pressure producing (generating) member, in accordance with the shape of the liquid container.
Specifically, one of the points the present invention aims at, in light of the problems of the prior arts as described above, is to provide a fiber body which can exhibit an ink supplying ability keeping up with the trends toward diversification of ink and high-speed printing and can make easier the ink injection, a liquid container having the same, and a method of subjecting the above fiber body to surface treatment of giving hydrophilic nature thereto.
Further, the present invention aims mainly at providing an epoch-making lyophilic surface reforming method which enables a desired lyophilic surface reforming neither by the technique of modifying the properties of a negative pressure producing member by allowing the same to have a radical using ozone and ultraviolet rays nor by the technique of applying primers such as silane coupling agent on the surface of an element, causing a non-uniform coating thereon, as described above, but by a novel mechanism; a treatment liquid for use in the above method; a negative pressure producing member obtained by the above method; and a surface structure itself obtained by the lyophilic surface reforming, in particular, a fiber negative pressure producing member having an excellent ability to return to the initial negative pressure even after repeating replenishment and an excellent ability to supply liquid. In particular, the present invention aims at providing a fiber absorber for use in liquid ejection and a liquid container with which desired properties, such as the property of decreasing resistance to flow of liquid during the liquid""s movement, can be obtained by modifying the properties of the fiber in the liquid container through changing the level of surface treatment of giving lyophilic nature to the surface of an element.
The present invention aims mainly at providing an epoch-making lyophilic surface reforming method which enables a desired lyophilic surface reforming neither by the technique of modifying the properties of a negative pressure producing member by allowing the same to have a radical with ozone and ultraviolet rays nor by the technique of applying primers such as silane coupling agent on the surface of an element, causing a non-uniform coating thereon, as described above, but by a novel mechanism; a treatment liquid for use in the method; a negative pressure producing member obtained by the method; and a surface structure itself obtained by the lyophilic surface reforming, in particular, a fiber negative pressure producing member having an excellent ability to return to the initial negative pressure even after repeating replenishment and an excellent ability to supply liquid.
The first object of the present invention is to provide a liquid treatment agent with which the entire internal surface of a negative pressure producing member having a complicated topology, such as porous body and finely processed element, can be subjected to surface treatment of giving a desired lyophilic nature thereto and a lyophilic surface reforming method using the liquid treatment agent.
The second object of the present invention is to provide a novel lyophilic surface reforming method which allows an olefin resin, which has been considered to be hard to subject to surface reforming, to retain lyophilic nature for a long period of time and a surface structure itself.
The third object of the present invention is to provide a novel lyophilic surface reforming method which enables the formation of a molecular level thin film, preferably a monomolecular level thin film, as a reformed surface itself, while causing no weight increase of a negative pressure producing member structure and a surface structure itself.
The fourth object of the present invention is to provide a surface treatment method which makes it possible to freely conduct a desired surface reforming by introducing a novel mechanism to lyophilic surface reforming method itself.
The fifth object of the present invention is to provide a method of producing a lyophilic surface treatment agent for use in the surface of a negative pressure producing member which is simple and excellent in mass productivity.
The sixth object of the present invention is to provide an epoch-making method of subjecting the surface of a negative pressure producing member to lyophilic surface treatment which utilizes, from the viewpoint of the interfacial energy of a functional group (or a group of functional groups) a polymer has, an interfacial physical adsorption at an energy level almost the same as that caused by the polymer cleavage.
The seventh object of the present invention is to provide a novel lyophilic surface reforming method which enables the uniform reforming of the periphery of a negative pressure producing member and a surface structure itself on a level which cannot be achieved by the prior arts in terms of its entire periphery.
The other objects of the present invention will be understood from the following description and the present invention can also achieve complex objects of the arbitrary combinations of each of the above object.
In order to achieve the above objects, the present invention is a negative pressure producing fiber body for use in a container for containing a liquid, which is to be supplied to a liquid ejecting head for ejecting the liquid for recording, in a manner that allows the liquid to be supplied, characterized in that it has an olefin resin at least on its fiber surface and the olefin resin has a lyophilic group in an oriented state on its surface.
The present invention is a fiber body for use in a container for containing a water-based liquid, which is to be supplied to a liquid ejecting head for ejecting the water-based liquid for recording, in a manner that allows the water-based liquid to be supplied, consisting of a fiber provided with a polymer at least part of its surface, characterized in that the above polymer includes a first portion having a hydrophilic group and a second portion having a group of which interfacial energy is lower than that of the above hydrophilic group and almost the same as the surface energy of the above part of the surface, the above second portion being oriented toward the above part of the surface, the above first portion being oriented in the direction different from the above part of the surface.
When the surface of the above fiber consists of an olefin resin, it s preferable that the above polymer is, for example, polyalkylsiloxane including a hydrophilic group and the above hydrophilic group have, for example, a polyalkylene oxide chain.
Preferably, the above olefin resin is polypropylene or polyethylene and the above polyalkylsiloxane is polyoxyalkylene-dimethylpolysiloxane.
The present invention is a liquid container containing the above fiber body as a negative pressure producing member.
The present invention is a liquid container including a negative pressure producing member containing portion for containing the above fiber body as a negative pressure producing member and a liquid containing portion for supplying liquid to the above negative pressure producing member containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit.
The above liquid containing portion may be constructed in such a manner as to include an inner bag for containing liquid, which becomes deformed as the liquid contained therein becomes led out and thereby can produce a negative pressure, a casing for covering the above inner bag, and an atmosphere communication port which can introduce atmosphere between the above casing and the above inner bag.
The above fiber body, as a negative pressure producing member, contained in the negative pressure producing member containing portion has a polyolefin resin on its entire surface and the above polyolefin resin has a hydrophilic group in a oriented state on its surface; accordingly, the surface of the fiber has a high wettability, which makes easier a liquid injection process even when the liquid has high surface tension. In addition, since the resistance to flow during the movement of recording liquid is decreased, it can keep up with the trend toward higher-speed printing, in particular, high flow rate liquid supplying to a liquid ejecting head.
The present invention is a liquid container which has a supply opening for supplying liquid to a liquid ejecting head and an atmosphere communication port for allowing the interior of the liquid container to communicate with the atmosphere, contains a negative pressure producing member, and is characterized in that a fiber body, as described above, is arranged in the interior portion of the above supply opening. Arranging a fiber body, which has been subjected to surface treatment of giving hydrophilic nature thereto, in the supply opening portion enables the decrease in resistance to ink flow and the increase in the ink""s flow characteristics, while obtaining a desired capillary attraction, and hence, the ink supplying of a high flow rate. Furthermore, it enables the prevention of bubble retention which is caused when using the fiber body as a pressure contact body, in this point, the increase in resistance to flow can be suppressed.
The present invention is a liquid container which has a supply opening for supplying liquid to a liquid ejecting head and an atmosphere communication port for allowing the interior of the liquid container to communicate with the atmosphere, contains a fiber body as a negative pressure producing member, and is characterized in that the above fiber body is partially subjected to surface treatment of giving lyophilic nature thereto only on the portion corresponding to the above supply opening and on the periphery portion thereof. Subjecting the fiber body to surface treatment of giving hydrophilic nature thereto only on the portions described above is also applicable to a liquid container which includes a negative pressure producing member containing portion for containing a fiber body as a negative pressure producing member, an atmosphere communication port for allowing the interior of the liquid container to communicate with the atmosphere, and a supply opening for supplying liquid held by the above fiber to a liquid ejecting head, and a liquid containing portion for leading out the liquid to the above negative pressure producing member containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit.
Subjecting the fiber body, as a negative pressure producing member, contained in the above liquid container to surface treatment of giving lyophilic nature thereto only on the portion corresponding to the supply opening and on the periphery portion thereof allows recording liquid to tend to exist on the supply opening and on the periphery thereof at all times; accordingly, the liquid supplying to a head is unlikely to be interrupted, in addition, bubbles are unlikely to flow in the recording head.
The present invention is a liquid container which includes a negative pressure producing member containing portion for containing a fiber body as a negative pressure producing member, an atmosphere communication port for allowing the interior of the above negative pressure producing member containing portion to communicate with the atmosphere, a supply opening for supplying liquid to a liquid ejecting head and a liquid containing portion for leading out the liquid to the above negative pressure producing member containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit, is characterized in that the above fiber body is partially subjected to surface treatment of giving lyophilic nature thereto only on the periphery of the planar layer existing over the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion and intersecting the gravity direction.
Subjecting the fiber body, as a negative pressure producing member, contained in the above liquid container to surface treatment of giving hydrophilic nature thereto on the planar layer which exists over the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion and intersects the gravity direction enables the diffusion of the liquid flowing though the fiber on the portion having been subjected to surface treatment of giving hydrophilic nature thereto, even when the liquid or gas in the liquid containing portion expands due to some change in environment. Thus, an abrupt increase in pressure can be relaxed in the direction of horizontal section without increasing the volume of the negative pressure producing member containing chamber.
The present invention is a liquid container which includes a negative pressure producing member containing portion for containing a fiber body as a negative pressure producing member, an atmosphere communication port for allowing the interior of the above negative pressure producing member containing portion to communicate with the atmosphere, a supply opening for supplying liquid to a liquid ejecting head and a liquid containing portion for leading out the liquid to the above negative pressure producing member containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit, is characterized in that the above fiber body is partially subjected to surface treatment of giving lyophilic nature thereto at least on the liquid supplying area from the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion to the above supply opening.
Partially subjecting the fiber body, as a negative pressure producing member, contained in the above liquid container to surface treatment of giving lyophilic nature thereto at least on the liquid supplying area from the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion to the above supply opening enables the prevention of a liquid level from prominently dropping on the area having been subjected to surface treatment of giving lyophilic nature thereto, even when the liquid level is disturbed during the gas-liquid exchange because of the micro difference in density the fiber body has. Thus, the movement of the liquid from the liquid containing portion to the negative pressure producing member containing portion is not interrupted by the air, and gas-liquid exchange operation is carried out stably. In addition, since the portion in the vicinity of the supply opening has been subjected to surface treatment of giving lyophilic nature thereto, the liquid tends to exist around the portion; accordingly, a recording liquid is hard to interrupt on the supply opening. Furthermore, when replacing the liquid containing portion with a new one, since the portion of the fiber body having been subjected to surface treatment of giving lyophilic nature thereto positively draws in the liquid, the recovery of a head is promptly achieved. And the amount of the liquid required for the head recovery can be controlled by varying the size of the area subjected to surface treatment of giving lyophilic nature thereto.
The present invention is a liquid container which includes a negative pressure producing member containing portion for containing a fiber body as a negative pressure producing member, an atmosphere communication port for allowing the interior of the above negative pressure producing member containing portion to communicate with the atmosphere, a supply opening for supplying liquid to a liquid ejecting head and a liquid containing portion for leading out the liquid to the above negative pressure producing member containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit, is characterized in that the above fiber body is partially subjected to surface treatment of giving lyophilic nature thereto on the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion.
The present invention is a liquid container which includes a negative pressure producing member containing portion for containing a fiber body as a negative pressure producing member, an atmosphere communication port for allowing the interior of the above negative pressure producing member containing portion to communicate with the atmosphere, a supply opening for supplying liquid to a liquid ejecting head, a liquid containing portion for leading out the liquid to the above negative pressure producing member containing portion and an atmosphere introducing channel, which is provided in the vicinity of the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion, for causing a gas-liquid exchange in which the liquid is led out to the above negative pressure producing member containing portion subsequently after gas is introduced into the above liquid containing portion, the above liquid containing portion and the above negative pressure producing member containing portion constituting an integrally or removably formed unit, is characterized in that the above fiber body is partially subjected to surface treatment of giving lyophilic nature thereto on the area corresponding to the above atmosphere introducing channel.
Partially subjecting the fiber body, as a negative pressure producing member, contained in the above liquid container to surface treatment of giving lyophilic nature thereto on the portion where the above negative pressure producing member containing portion communicates with the above liquid containing portion or the area corresponding to the above atmosphere introducing channel allows the liquid to be stably held by the portion having been made lyophilic, which can prevent gas-liquid exchange operation from starting, due to inadvertent air pass, when the gas-liquid exchange is still premature. Further, when the consumption of a recording liquid stops in the gas-liquid exchange state, the atmosphere communication channel or the atmosphere communication portion can be closed promptly by filling the portion of the fiber body corresponding to the atmosphere introducing channel with the liquid. Due to the functions described above, a stable gas-liquid exchange operation becomes made possible. In addition, when removing the above liquid container so as to replace it with a new one, the liquid is unlikely to drop from the communication portion on the side of the above negative pressure producing member containing portion.
The liquid container of which fiber body has been partially subjected to surface treatment of giving lyophilic nature thereto may be constructed in such a manner as to include an inner bag for containing liquid, which becomes deformed as the liquid contained therein becomes led out and thereby can produce a negative pressure, a casing for covering the above inner bag, and an atmosphere communication port which can introduce atmosphere between the above casing and the above inner bag.
The present invention is a method of subjecting a fiber body, as a negative pressure producing member, contained in a liquid container having a supply opening for supplying liquid to a liquid ejecting head and an atmosphere communication port for allowing the interior of the liquid container to communicate with the atmosphere, besides the fiber body, to surface treatment of giving lyophilic nature thereto on the portion corresponding to a supply opening and the periphery thereof, comprising the steps of: injecting the above lyophilic treatment agent into the vicinity of the central portion of the above fiber body by using a syringe containing the above lyophilic treatment agent and inserting the needle of the syringe into the above fiber body through the above atmosphere communication port; and sucking up the above lyophilic treatment agent through the above supply opening and discharging the same before the above lyophilic treatment agent reaches the inner surface of the above liquid container.
In order to achieve the above objects, the fiber absorber of the present invention for use in liquid ejection is a fiber absorber for use in an ink jet apparatus which consists of an olefin resin fiber and is contained in a liquid container of the apparatus so as to hold a liquid supplied to a liquid ejecting head under a negative pressure, characterized in that it has at least one portion having been subjected to surface treatment of giving lyophilic nature thereto on the surface of the fiber and the above portion having been subjected to surface treatment of giving lyophilic nature has a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
Another aspect of the fiber absorber of the present invention for use in liquid ejection is a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has a polymer compound provided on at least part of its surface which should be subjected to surface treatment of giving lyophilic nature thereto and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, characterized in that the above polymer compound has a first portion having a lyophilic group and a second portion having a group of which interfacial energy is lower than that of the above lyophilic group but is almost the same as the surface energy of the above surface part to be subjected to the above surface treatment and the portion having been subjected to surface treatment of giving lyophilic nature thereto and having lyophilic nature is obtained in such a manner as to orient the above second portion toward the above surface part and the above first portion in the direction different from the above surface part, the above surface part having a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area of which density decreases with the increase in distance away from the above first lyophilic area.
Another aspect of the fiber absorber of the present invention for use in liquid ejection is a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has a lyophobic surface at least part of which has been subjected to surface reforming to have a lyophilic nature and is contained in a liquid container for holding a liquid supplied to a liquid ejecting head under a negative pressure,
characterized in that it has a lyophilic portion obtained by attaching the fragmented portions (fragment) having a lyophilic or a lyophobic group, which has been produced by the cleavage of polymer (compound) having both lyophilic and lyophobic groups, on the above lyophobic surface in such a manner as to orient the above lyophobic group toward the above lyophobic surface and in the direction different from the above lyophilic group,
the above lyophilic portion having a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
Another aspect of the fiber absorber of the present invention for use in liquid ejection is a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has an olefin resin at least on its surface at least part of which is a reformed to have lyophilic nature and is contained in a liquid container for holding a liquid supplied to a liquid ejecting head under a negative pressure,
characterized in that the fiber of the fiber absorber has a wettable surface structure having a relatively long chain lyophilic group and a relatively short chain lyophobic group alternately which is obtained in the following steps of: attaching on the surface of said fiber a treatment agent containing a polymer, which has a hydrophilic group and a group, as a constituent of the above olefin resin, having an interfacial energy almost the same as the surface energy of said olefin-based fiber surface thereon, a dilute acid as a catalyst for said polymer cleavage and alcohol; subjecting said polymer to cleavage by evaporating the treatment agent attached on the surface of said fiber and allowing said dilute acid to be a concentrated acid; and condensing the product of the polymer cleavage,
the above wettable surface structure having a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
As described above, according to the fiber absorber of the present invention for use in liquid ejection, since the fiber absorber can be subjected to surface treatment of giving lyophilic nature thereto while allowing the lyophilic nature to have a distribution, the resistance to liquid flow in the fiber absorber can be freely set according to the need while utilizing the behavior of the lyophilic group (this is based on the fact that the more lyophilic groups, the lower resistance to flow). Thus, the fiber absorber allows a liquid to be held in the liquid container and supplied to a liquid ejecting head in an optimal state according to the liquid behavior required in the liquid container.
A liquid container of the present invention has a container casing which includes a supply opening for supplying a liquid to a liquid ejecting head and an atmosphere communication port for communicating with the atmosphere and a fiber absorber for use in liquid ejection which is selected from those of the present invention described above and contained in the above container casing to hold the liquid therein using a negative pressure.
According to the liquid container described above, a liquid can be held therein and supplied to a liquid ejecting head in an optimal state by arranging a first lyophilic area of the fiber absorber for use in liquid ejection in a predetermined position of the liquid container according to the liquid behavior.
More specifically, the liquid container of the present invention has a container casing which includes a supply opening for supplying a liquid to a liquid ejecting head and an atmosphere communication port for communicating with the atmosphere and a fiber absorber which consists of an olefin resin, has been subjected to surface treatment of giving lyophilic nature thereto at least on part thereof in such a manner as to be allowed to have stronger lyophilic nature as it becomes away from the above supply opening, and is contained in the above container casing to hold the liquid therein using a negative pressure.
According to the liquid container described above, since the fiber absorber contained in the container casing has been subjected to surface treatment of giving lyophilic nature thereto in such a manner as to be allowed to have more lyophilic groups (stronger lyophilic nature) as it becomes away from the above supply opening, the resistance of liquid flow becomes smaller at a location away from the supply opening. As a result, even at a location away from the supply opening, the liquid flows easily toward the supply opening, which improves the efficiency of using the liquid in the liquid container. With respect to liquid injection into the liquid container, as long as it is done from the area having stronger lyophilic nature, the liquid can be injected into the liquid container without drawing a vacuum therein.
Another aspect of the liquid container of the present invention has a container casing which includes a supply opening for supplying a liquid to a liquid ejecting head and an atmosphere communication port for communicating with the atmosphere and a fiber absorber which consists of an olefin resin, has been subjected to surface treatment of giving lyophilic nature thereto at least in the vicinity of the above supply opening in such a manner as to be allowed to have weaker lyophilic nature as it becomes away from the above supply opening, and is contained in the above container casing to hold the liquid therein using a negative pressure.
According to the liquid container described above, since the fiber absorber contained in the container casing has been subjected to surface treatment of giving lyophilic nature thereto in the vicinity of the supply opening in such a manner as to be allowed to have weaker lyophilic nature as it becomes away from the above supply opening, the liquid can be held without increasing the resistance to liquid flow in the vicinity of the supply opening, which prevents the liquid supplying to the liquid ejecting head from being interrupted. With respect to liquid injection into the liquid container, it can be done from the supply opening without drawing a vacuum therein.
Another aspect of the liquid container of the present invention has a negative pressure producing member containing chamber which includes a supply opening for supplying a liquid to a liquid ejecting head and an atmosphere communication port for communicating with the atmosphere and contains therein a fiber absorber consisting of an olefin resin for holding a liquid under negative pressure; and a liquid containing chamber which communicates with the above negative pressure producing member containing chamber and has a liquid containing portion substantially in a sealed state except the portion communicating with the above negative pressure producing member containing chamber, the above fiber absorber existing over the above communication portion as a layer intersecting the gravity direction and having a portion having been subjected to surface treatment of giving lyophilic nature thereto in such a manner as to be allowed to have weaker lyophilic nature on its upper portion.
In the above liquid container, once the liquid in the negative pressure producing member containing chamber is consumed to such a extent that the liquid level thereof reaches the portion communicating with the liquid containing portion, then the communication portion starts to communicate with the atmosphere via the atmosphere communication portion of the negative pressure producing member containing chamber and the fiber absorber, and the air is introduced into the liquid containing chamber. At the same time, the liquid in the liquid containing chamber moves to the negative pressure producing member containing chamber via the communication portion, which allows the negative pressure in the negative pressure producing member containing chamber to be kept constant.
If the liquid and gas in the liquid containing chamber abruptly expand due to environmental changes etc., the liquid in the liquid containing chamber flows in the negative pressure producing member containing chamber; however, the liquid is absorbed into the fiber absorber by the buffer function of the negative pressure producing member containing chamber. Since the fiber absorber exists over the above communication portion as a layer intersecting the gravity direction and has a portion having been subjected to surface treatment of giving lyophilic nature thereto in such a manner as to be allowed to have weaker lyophilic nature on its upper portion, the liquid having flowed into the negative pressure producing member containing chamber is trapped into the portion having been subjected to surface treatment of giving lyophilic nature thereto from the lower to the upper portion in sequence. Thus, even if the upper volume of the negative pressure producing member containing chamber is not needlessly large, the buffer function described above is fully performed.
Further, the present invention provides a method of producing the above-described fiber absorber of the present invention for use in liquid ejection. One aspect of the method is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has a lyophilic group provided at least on the part of its surface which should be subjected to surface treatment of giving lyophilic nature thereto and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including a first step of providing a liquid, which contains a polymer including a first portion having the above lyophilic group and a second portion having a group of which interfacial energy is different from that of the above lyophilic group but is almost the same as the surface energy of the above surface part to be subjected the above surface treatment, to the part which should be subjected to surface treatment of giving lyophilic nature thereto in such a manner as to form a first area where the density of the liquid provided is relatively high and a second area where the density of the same is relatively low; and a second step of obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to orient the above second portion of the above polymer toward the above surface part and the above first portion of the same in the direction different from the above surface part.
Another aspect of the method of producing a fiber absorber of the present invention for use in liquid ejection is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has a lyophilic group provided at least on the part of its surface which should be subjected to surface treatment of giving lyophilic nature thereto and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including a first step of providing the above part of the surface with a liquid containing a fragmented product which has a first portion with a lyophilic group and a second portion with a group having an interfacial energy different from that of the above lyophilic group but almost the same as the surface energy of the above part of the surface, the above fragmented product being obtained by subjecting a polymer to cleavage which has the above first and second portions in such a manner as to form a first area where the density of the liquid provided is relatively high and a second area where the density of the same is relatively low; and a second step of obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to orient the second portion of the above fragmented product toward the above part of the surface and the above first portion of the same in the direction different from the above part of the surface; and a third step of condensing at least part of the oriented portions of the above fragmented product on the above part of the surface into a polymer.
Another aspect of the method of producing a fiber absorber of the present invention for use in liquid ejection is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has an olefin resin at least on its surface, has a lyophilic group provided at least on the part of the above surface, and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including a first step of providing the above part of the surface with a liquid in which a polymer of alkylsiloxane including a lyophilic group is dissolved in such a manner as to form a first area where the density of the liquid provided is relatively high and a second area where the density of the same is relatively low; and a second step of obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to orient the above alkylsiloxane toward the above part of the surface and the above lyophilic group in the direction different from the above part of the surface.
Another aspect of the method of producing a fiber absorber of the present invention for use in liquid ejection is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has an olefin resin at least on its surface, has a lyophilic group provided at least on the part of the above surface, and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including a first step of providing the above part of the surface with a liquid in which a fragmented product obtained by subjecting a polymer of alkylsiloxane including a lyophilic group to cleavage is dissolved in such a manner as to form a first area where the density of the liquid provided is relatively high and a second area where the density of the same is relatively low; and a second step of obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to condense the above fragmented product on the above part of the surface, in addition, orient the above alkylsiloxane toward the above part of the surface and the above lyophilic group in the direction different from the above part of the surface.
Another aspect of the method of producing a fiber absorber of the present invention for use in liquid ejection is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has an olefin resin at least on its surface, has a lyophilic group provided at least on the part of the above surface, and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including the steps of: forming a fiber surface having a liquid, which contains polyalkylsiloxane, acid and alcohol, attached thereon in such a manner as to form a first area where the density of the liquid attached is relatively high and a second area where the density of the same is relatively low; and obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to heat and dry the liquid attached on the above fiber surface at temperatures higher than room temperature and lower than the melting point of the above olefin resin.
Another aspect of the method of producing a fiber absorber of the present invention for use in liquid ejection is a method of producing a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has an olefin resin at least on its surface, has a lyophilic group provided at least on the part of the above surface, and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure, the method including the steps of: forming a fiber surface having a liquid, which contains polyalkylsiloxane, acid and alcohol, attached thereon in such a manner as to form a first area where the density of the liquid attached is relatively high and a second area where the density of the same is relatively low; and obtaining a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature in such a manner as to dry the liquid attached on the above fiber surface and, during the drying process, orientate the above lyophilic group in the direction opposite to the above fiber surface so as to subjecting the fiber surface to surface treatment of giving lyophilic nature thereto.
A surface reforming method of the present invention is a method of subjecting the a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection which has a lyophobic surface and is used for holding a liquid supplied to a liquid ejecting head under a negative pressure to surface reforming so as to reform the above lyophobic surface into a lyophilic one, characterized in that it includes a step of attaching on the above lyophobic surface a fragmented product having both lyophilic and lyophobic groups, which is produced by subjecting a polymer having both lyophilic and lyophobic groups to cleavage, in such a manner as to orient the above lyophobic group toward the surface and the above lyophilic group in the direction different from that of the above lyophobic group so as to have a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
Another aspect of the surface reforming method of the present invention is a method of subjecting a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection to surface reforming on part of its surface, characterized in that the surface reforming is performed in such a manner as to condense a cleavage polymer, which has been oriented in accordance with the affinity of the interfacial energy of a group similar to the surface energy of the part of the surface of the above fiber, on the above part of the surface, so as to have a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
Another aspect of the surface reforming method of the present invention is a method of subjecting a fiber absorber, as an assembly of numbers of fibers, for use in liquid ejection to surface reforming on part of its surface using a liquid polymer, characterized in that it includes a condensation step of condensing a polymer fragmented product, which has a first group which can be subjected to cleavage and condensation and comprises a lyophilic group and a second group of which interfacial energy is almost the same as the surface energy of the part of the surface of the above fiber, into a polymer on the above part of the surface, so as to have a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
A wettable surface structure of the fiber assembly of the present invention is a wettable surface structure of a fiber assembly used for holding a liquid to be supplied to a liquid ejecting head under negative pressure, characterized in that it has a lyophilic portion including a polymer having relatively long chain lyophilic groups and relatively short chain lyophobic groups alternately, the above lyophilic portion having a first lyophilic area relatively superior in lyophilic nature and a second lyophilic area relatively inferior to the above first lyophilic area in lyophilic nature.
The terms xe2x80x9clyophilic area relatively superior in lyophilic naturexe2x80x9d used herein means any of the cases where the area shows stronger lyophilic nature than the other lyophilic areas because it has more lyophilic groups per area than the others and where the area can maintain a relatively lyophilic state for a longer period of time because lyophilic groups are attached on the area more strongly than the other lyophilic areas.
On the other hand, the terms xe2x80x9clyophilic area relatively inferior in lyophilic naturexe2x80x9d used herein means any of the cases where the area shows weaker lyophilic nature than the other lyophilic areas and where the area can maintain a relatively lyophilic state only for a shorter period of time.